1. Field of the Invention
The present invention relates to an LED light-emitting module and an illumination apparatus using the same, and more particularly, to an LED light-emitting module with excellent heat radiating characteristics whose light radiation angle can be easily adjusted, and an illumination apparatus using the same.
2. Description of the Related Art
In recent years, LEDs are being studied as an illumination unit due to their low power consumption and long lifespan as compared with general light sources. As heat generated in LED packages shortens the lifespan, structures for smoothly radiating the heat of the LED packages are also being widely studied and developed.
In particular, while it is required to enhance the heat radiating characteristics of an LED street lamp employing a plurality of LED packages, there is a limit in enhancing smooth heat radiating characteristics with a structure in which heat radiating fins are provided on the rear surface of a printed circuit board (PCB) having a plurality of LED packages. In spite of many efforts to enhance heat radiating characteristics by increasing the number and height of heat radiating fins, there is also a limit in improving heat radiating characteristics as air cannot be convected in spaces between the heat radiating fins.
Japanese Utility Model No. 3163002 (hereinafter, the conventional technology) discloses an example of a structure for preventing lowering of heat radiating efficiency due to an increase in the height of heat radiating fins toward the rear side of a mounting surface of an light emitting diode (LED) used as an illumination means.
The conventional technology discloses an improved illumination apparatus adapted to smoothly emit heat due to air introduced between high heat radiating fins by crossing heat radiating fins of different shapes and heights toward the rear side of a mounting surface of an LED.
However, as it is relatively difficult to manufacture heat radiating fins of different heights, and there is a need to process groove patterns for easy flow of air in a central upper side of the heat radiating fins, manufacturing costs increase and productivity decreases.
Moreover, in the conventional technology, while a housing protrudes from a side of the LED mounting surface contacting a board to which LED chips are mounted, toward a lower side and some of the heat radiating fins are placed outside the protruding portion, the heat radiating fins on the side have an area remarkably small as compared with the area of the heat radiating fins placed on the rear side of the LED mounting surface, resulting in a very small amount of radiated heat.
This is because, considering that heat radiating efficiency is basically proportional to the area of the heat radiating fins to a certain degree, heat radiating effect is low and heat is radiated mainly to the rear side of the LED mounting surface, resulting in lowering of heat radiating efficiency.
In addition, in the conventional technology, there exist portions of a frame except for an area of the heat radiating fins whose thicknesses are partially different from the other portions, in which case the lifespan of some of the LED chips becomes shortened due to partial non-uniformity of temperatures caused by differences between the thicknesses of the frame, resulting in a shortened lifespan of the entire LED light-emitting apparatus.
Meanwhile, as an LED package has a narrow light radiating angle as compared with a general light source of a different type lamp, a more complex mechanical structure is needed to comply with a minimal light radiation angle range of a street lamp which is also related to the height of the street lamp. However, it is not easy to design such a structure and without increasing manufacturing costs.
Moreover, required illumination intensities may be different according to the locations of LED street lamps. Thus, since there is a need to consider the number of LED packages in designing the conventional LED street lamp from the start of the design, additional designs and manufactures are required for illumination apparatuses of different illumination intensities.
Although the conventional technology can satisfy the illumination intensity issue when a plurality of illumination apparatuses are disposed in parallel, they respectively include a rotor for rotation, making their mechanisms for individually driving the rotors very complex and making it difficult to configure the mechanisms. Further, the outwardly protruding rotors contact a coupling plate, making it difficult to adjust their angles.